New IP aggregation (“IPAG”) networks use a layered architecture, including OSI Layer-2 (L2) aggregation or access packet switches, connected by physically diverse fiber paths to a “cluster” of IPAG core network backbone packet switches. Layer-2 is a protocol layer in the Open Systems Interconnection (OSI) protocol stack and includes protocols such as Ethernet VLAN (Virtual Local Area (LAN) Network) and Multiprotocol Label Switching (MPLS). The term “IP aggregation” represents the idea that Ethernet frames, including IP packets, are collected on the edge of the IPAG network and then, for network efficiency and compatibility with typical enterprise LANs, encapsulated into L2 protocol data units and then routed via the L2 packet switches, which do not rely on IP (OSI Layer-3) addressing to route the encapsulated packets within the IPAG network. For example, VPWS (Virtual Pseudo Wire Service) may be used for point-to-point connections and VPLE for multipoint services. IPAG switches are typically connected to a MPLS backbone network. While this embodiment concentrates on metropolitan networks, IPAG network covers a variety of other networks referred to in the telecommunications literature, such as Metropolitan Ethernet Network, Packet-Access Network, Metropolitan Area Network (MAN), and Wide Area Network (WAN). Example services provided by the IPAG networks include enterprise Ethernet services and cellular backhaul (virtual packet connectivity between cellular basestations and their Mobile Telephone Switching Offices (MTSOs)). These packet virtual services are often provided by a protocol stack called Virtual Private LAN Service (VPLS) developed by the Internet Engineering Task Force (IETF). In turn, the backbone network devices are connected via diverse paths to an IPAG Gateway switch for connecting the IPAG network to an IP (Internet Protocol) backbone network, usually provided by an Internet Service Provider (ISP), for further routing between cities or countries. In addition and consistent with the IP aggregation concept, the IPAG Gateway will typically convert the VPLS-based protocol data units to IP-based flows or MPLS tunnels that are typical of IP backbone networks. However, note that this embodiment of the IPAG network architecture is not restricted to metropolitan area networks and, thus, can be deployed to cover inter-city networks. In such latter cases the IPAG Gateway (or multiple Gateways) could interconnect to other metropolitan IPAG networks or establish peering relationships with other IP backbone networks. The networks present a large and complex design problem. Thus there exists a need for comprehensive tools for designing networks including both access nodes and backbone nodes.